220 Mr. A. Alcock on the Bathybial Fishes 
minute and the ventrals singularly large, and there is a con- 
spicuous luminous organ immediately in front of the eye ; the 
dorsal fin is nearer to the snout than to the base of the caudal 
and entirely in front of the anal. But the single specimen 
has been too much damaged to become the type of a new species 
and the subject of a description. 
Family StomiaticUe. 
Thaumastomias, gen. nov. 
Allied to Malacosteus , Ayres. 
Body elongate, compressed, scaleless, with the vent not far 
distant from the caudal fin. Head compressed, with the 
cranium small, the snout short, and the cleft of the mouth 
exceedingly wide. A long elastic muscular band passing 
from the hyoid bone to the inner aspect of the mandibular 
symphysis. Teeth acute, unequal, in single series in pre- 
maxillse, maxillse, mandibles, and palatines ; none on the 
tongue. Eye moderate. Gill-covers rudimentary. One 
dorsal fin opposite to the anal, situated in the posterior fourth 
of the body, near the caudal. No pectoral fins. Ventral 
fins situated in the anterior half of the body. Gill-openings 
very wide. No air-bladder. 
22. Thaumastomias atrox , sp. n. (PI. VIII. fig. 7.) 
Head small, mouth extremely wide. Body elongate, low, 
compressed, not diminishing much to the origin of the vertical 
fins, but there rapidly and symmetrically narrowing to the 
caudal peduncle, which is not quite one fifth the body-height 
in depth. 
D. 23. A. 25. C. circ. 25. P. 0. V. 6. 
Length of the head one fifth, height of the body one tenth, 
of the total without the caudal. 
Snout truncated, broad, with a slightly concave vertical 
profile, its length one third the diameter of the eye. Eye 
large, circular, its diameter about one fourth the length of the 
head ; interorbital space wider than the eye, convex. On 
each side there is a small luminous organ, about the size and 
shape of a caraway-seed, below and partly in front of the 
eye, and another large salient slipper-shaped one, in length 
more than one third the length of the head, lying parallel 
with the upper jaw behind the eye. Mouth enormous, its 
cleft as long as the head ; its floor is completely wanting 
